EP627 - Trends In Treatment Recommendations For Distal Rectal Cancer From Four NAPRC Hospitals In A Single Healthcare System

Purpose/Background: Trends in the treatment of rectal cancer (RC) have changed significantly over recent decades with a shift toward total neoadjuvant therapy (TNT) for the reduction of local recurrence as well as organ preservation and the introduction of Watch and Wait (WW) protocols. Anal sphincter (AS) preservation in patients with distal rectal cancer is associated with decreased morbidity and obviates the need for permanent stoma. To evaluate recent trends in distal rectal cancer treatment, we analyzed data from 4 NAPRC approved hospitals within a single healthcare system.

Methods/Interventions: Data from 4 hospitals' NAPRC accredited tumor boards (TB) from 2020-2025 was entered into a system-wide REDCap database. Recommendations from the initial TB presentation were analyzed, along with subsequent post-neoadjuvant TB recommendations and surgical outcomes data. Information including diagnostic imaging results, clinical staging, neoadjuvant therapy regimens, and surgical pathology were analyzed.

Results/Outcomes: A total of 477 RC patients' data was reviewed; 151 (32%) had distal rectal cancers (0-5.0cm from anal verge). There were 87 males (57.6%) and 64 females (42.4%) with a mean age of 65.7 years. MRI determined tumor distance from the anal verge averaged 3.0 cm (SD=1.7cm). Per MRI, pre-treatment AS involvement (ASI) was present in 75 patients (49.7%). Neoadjuvant treatment was recommended for 132 patients (87.4%), surgery for 16 patients (10.6%), and observation for 3 (2.0%). Neoadjuvant treatment was more likely to be recommended for distal-RC (87.4%) than mid-RC (73.2%), or proximal-RC (56.2%). TNT was the predominant neoadjuvant recommendation (108 pts, 81.8%) followed by systemic chemotherapy (SC) (14 pts, 10.6%), and immunotherapy (3 pts, 2.3%). In patients who underwent TNT, the treatment sequence was chemoradiation therapy (CRT) followed by SC in 57.0% (53 pts) and SC followed by CRT in 43.0% (40 pts). In patients with pre-treatment ASI who underwent neoadjuvant treatment (n=52), post-treatment MRI showed resolution of ASI in 52% (n=27). Post-neoadjuvant recommendations for patients with resolution of ASI included WW in 18 patients (67%) with surgery in 8 (30%). For patients with residual ASI (n=25), surgery was recommended in 18 patients (72%), with WW in 5 patients (20%) and SC in 2 (8.0%). In the cohort with post-neoadjuvant resolution of ASI, sphincter preservation (WW, transanal excision, LAR) was achieved in 20/27 patients (74%) vs 12/25 patients (48%) in the group with persistent ASI. In patients without pre-treatment ASI who underwent neoadjuvant treatment, sphincter preservation was achieved in 40/48 patients (83%).

Conclusion/Discussion: Paradigm shifts in treatment recommendations for rectal cancer have led to increasing utilization of TNT, especially in patients with distal rectal cancer. Neoadjuvant treatment, most commonly TNT, is associated with tumor downstaging, resolution of ASI, and frequent utilization of watch and wait protocols with subsequent increases in sphincter preservation. In our cohort, the rate of sphincter preservation in patients with post-neoadjuvant resolution of ASI neared that of those without pre-treatment ASI, whereas persistent post-neoadjuvant ASI was associated with significantly decreased sphincter preservation. Compiling and analyzing data from multiple NAPRC multi-disciplinary tumor boards provides valuable insights into trends in RC treatment.

Post-neoadjuvant Recommendations by Anal Sphincter Involvement
Post-neoadjuvant recommendations for patients with pre-treatment anal sphincter involvement (ASI) per MRI and who underwent post-neoadjuvant MRI. NAPRC tumor board bases recommendations on imaging findings, tumor marker levels, and clinical evaluation with digital exam and/or endoscopy.